Ontogenic Development of Corticotrophs in Fetal Buffalo (Bubalus Bubalis) Pituitary Gland

To evaluate the subpopulation of corticotrophs in developing buffalo (Bubalus bubalis) fetus, pituitary glands were recovered (n=6 per group) from late first, second and third gestational female buffalo dams. The corticotrophs were identified by using specific antibodies against proopiomelanocortin (POMC) and adrenocorticotrophic hormone (ACTH) through immunohistochemistry. There was a significant (P≤0.05) increase of immunoreactive (ir) ir-ACTH cells during late 2^nd trimester while, ir-POMC cells were more (P≤0.05) at late 3^rd trimester of gestation as compared to other age groups. The quantity of co-localized cells for POMC and ACTH was significantly (P≤0.05) greater at the end of 1^st gestation rather than 2^nd and 3^rd gestational fetal adenohypophyseal cells. This study is the first to demonstrate co-localization of POMC+ACTH and the affect of gestational age on the expression of these cells in buffalo fetus adenohypophysis.Key words: buffalo, corticotrophs, fetus, pituitary gland, immunohistochemistry     

Levels of DNA strand breaks and superoxide in phorbol ester-treated human granulocytes

Phorbol ester treatment of granulocytes triggers release of superoxide (O) and a concomitant burst of DNA strand breaks. The relationship between the amount of O and the number of DNA breaks has not previously been explored. To quantify the relatively large amount of O generated over a 40-min period by 1 × 10⁶ granulocytes/mL, a discontinuous “10-min pulse” method employing cytochrome c was used; 140 nmol O per 1 × 10⁶ cells was detected. DNA strand breaks were quantified by fluorimetric analysis of DNA unwinding (FADU). To vary the level of O released by cells, inhibitors of the respiratory burst were used. Sodium fluoride (1–10 mM) and staurosporine (2–10 nM) both inhibited O production. In both cases, however, inhibition of strand breakage was considerably more pronounced than inhibition of O. Zinc chloride (50–200 μM) inhibited both O and DNA breaks, approximately equally. Dinophysistoxin-1 (okadaic acid) inhibited O production more effectively than it inhibited DNA breaks. O dismutes to H₂O₂, a reactive oxygen species known to cause DNA breaks. The addition of catalase to remove extracellular H₂O₂ had no effect on DNA breakage. Using pulse field gel electrophoresis, few double-stranded breaks were detected compared to the number detected by FADU, indicating that about 95% of breaks were single-stranded. The level of DNA breaks is not directly related to the amount of extracellular O or H₂O₂ in PMA-stimulated granulocytes. We conclude that either an intracellular pool of these reactive oxygen species is involved in breakage or that the metabolic inhibitors are affecting a novel strand break pathway. J. Cell. Biochem. 66:219–228, 1997. © 1997 Wiley-Liss Inc.     

Role of yeast domination in Indian idli batter fermentation

Adding Saccharomyces cerevisiae, along with natural bacterial flora of the ingredients, was the best method for standardizing idli termentation in terms of improved organoleptic characteristics, leavening and nutritional constituents.The authors are with the Department of Microbiology, Guru Nanak Dev University, Amristsar-143 005, India. GNDU IN. S.K. Soni is the corresponding author.     

TbTRF suppresses the TERRA level and regulates the cell cycle-dependent TERRA foci number with a TERRA binding activity in its C-terminal Myb domain

Telomere repeat-containing RNA (TERRA) has been identified in multiple organisms including Trypanosoma brucei, a protozoan parasite that causes human African trypanosomiasis. T. brucei regularly switches its major surface antigen, VSG, to evade the host immune response. VSG is expressed exclusively from subtelomeric expression sites, and we have shown that telomere proteins play important roles in the regulation of VSG silencing and switching. In this study, we identify several unique features of TERRA and telomere biology in T. brucei. First, the number of TERRA foci is cell cycle-regulated and influenced by TbTRF, the duplex telomere DNA binding factor in T. brucei. Second, TERRA is transcribed by RNA polymerase I mainly from a single telomere downstream of the active VSG. Third, TbTRF binds TERRA through its C-terminal Myb domain, which also has the duplex DNA binding activity, in a sequence-specific manner and suppresses the TERRA level without affecting its half-life. Finally, levels of the telomeric R-loop and telomere DNA damage were increased upon TbTRF depletion. Overexpression of an ectopic allele of RNase H1 that resolves the R-loop structure in TbTRF RNAi cells can partially suppress these phenotypes, revealing an underlying mechanism of how TbTRF helps maintain telomere integrity.     

A genetic assay for aneuploidy: quantitation of chromosome loss using a mouse/human monochromosomal hybrid cell line

A genetic assay is described in which a mouse/human hybrid cell line R3-5 containing a single human chromosome (a monochromosomal hybrid) is used to detect chemically induced aneuploidy. In this assay the frequency of chromosome loss determined by the cloning efficiency of the cells in a selection medium is used as an index for the potential of a chemical to induce aneuploidy. The hybrid cells are deficient in hypoxanthine guanine phosphoribosyltransferase (HGPRT) and contain human chromosome 2, marked with Ecogpt, an E. coli gene for xanthine guanine phosphoribosyltransferase. These cells with a genotype of hgprt-/Ecogpt+ can grow in medium containing mycophenolic acid and xanthine (MX medium) but not in medium containing 6-thioguanine (6-TG). The loss of the human chromosome from R3-5 cells as a result of chemical treatment produces cells with a genotype of hgprt-/Ecogpt- which are capable of growth in the medium containing 6-TG. Thus, the cloning efficiency of cells treated with a test chemical in 6-TG provides a method to determine the frequency of cells that have lost the human chromosome. Two chemicals, colcemid and nocodazole, previously known to induce aneuploidy in mammalian cells were used for a preliminary evaluation of this test system. Both of these compounds at concentrations ranging from 0.002 to 0.032 micrograms/ml showed a concentration-related positive response in this assay.     

Genetic analysis and QTL mapping of the seed hardness trait in a black common bean (<Emphasis Type="Italic">Phaseolus vulgaris</Emphasis>) recombinant inbred line (RIL) population

Seed hardness trait has a profound impact on cooking time and canning quality in dry beans. This study aims to identify the unknown genetic factors and associated molecular markers to better understand and tag this trait. An F_2:7 recombinant inbred line (RIL) population was derived from a cross between the hard and soft seeded black bean parents (H68-4 and BK04-001). Eighty-five RILs and the parental lines were grown at two locations in southern Manitoba during years 2014–2016. Seed samples were harvested manually at maturity to test for seed hardness traits. The hydration capacity and stone seed count were estimated by soaking the seeds overnight at room temperature following AACC method 56-35.01. Seed samples from 2016 tests were also cooked to determine effect of seed hardness on cooking quality. For mapping of genomic regions contributing to the traits, the RIL population was genotyped using the genotype by sequencing (GBS) approach. The QTL mapping revealed that in addition to the major QTL on chromosome 7 at a genomic location previously reported to affect seed-hydration, two novel QTL with significant effects were also detected on chromosomes 1 and 2. In addition, a major QTL affecting the visual appeal of cooked bean was mapped on chromosome 4. This multi-year-site study shows that despite large environmental effects, seed hardness is an oligo-genic and highly heritable trait, which is inherited independently of the cooking quality scored as visual appeal of cooked beans. The identification of the QTLs and development of SNP markers associated with seed hardness can be applied for common bean variety improvement and genetic exploitation of these traits.